drbd: Improve compatibility with drbd's older than 8.3.7
Regression introduced with 8.3.11 commit:
drbd: Take a more conservative approach when deciding max_bio_size
Never ever tell an older drbd, that we support more than 32KiB
in a single data request (packet).
Never believe an older drbd, that is supports more than 32KiB
in a single data request (packet)
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 1d71b3a..6035784f 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1284,7 +1284,8 @@
#endif
#define DRBD_MAX_BIO_SIZE_SAFE (1 << 12) /* Works always = 4k */
-#define DRBD_MAX_SIZE_H80_PACKET (1 << 15) /* The old header only allows packets up to 32Kib data */
+#define DRBD_MAX_SIZE_H80_PACKET (1 << 15) /* Header 80 only allows packets up to 32KiB data */
+#define DRBD_MAX_BIO_SIZE_P95 (1 << 17) /* Protocol 95 to 99 allows bios up to 128KiB */
extern int drbd_bm_init(struct drbd_conf *mdev);
extern int drbd_bm_resize(struct drbd_conf *mdev, sector_t sectors, int set_new_bits);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 72b1dfa..448de7b 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1075,6 +1075,12 @@
p = drbd_prepare_command(mdev, sock);
if (!p)
return -EIO;
+
+ if (mdev->tconn->agreed_pro_version <= 94)
+ max_bio_size = min_t(int, max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
+ else if (mdev->tconn->agreed_pro_version < 100)
+ max_bio_size = min_t(int, max_bio_size, DRBD_MAX_BIO_SIZE_P95);
+
p->d_size = cpu_to_be64(d_size);
p->u_size = cpu_to_be64(u_size);
p->c_size = cpu_to_be64(trigger_reply ? 0 : drbd_get_capacity(mdev->this_bdev));
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index f923462..838c3cd 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1062,10 +1062,13 @@
BIOs for a single peer_request */
if (mdev->state.conn >= C_CONNECTED) {
if (mdev->tconn->agreed_pro_version < 94)
- peer = mdev->peer_max_bio_size;
+ peer = min_t(int, mdev->peer_max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
+ /* Correct old drbd (up to 8.3.7) if it believes it can do more than 32KiB */
else if (mdev->tconn->agreed_pro_version == 94)
peer = DRBD_MAX_SIZE_H80_PACKET;
- else /* drbd 8.3.8 onwards */
+ else if (mdev->tconn->agreed_pro_version < 100)
+ peer = DRBD_MAX_BIO_SIZE_P95; /* drbd 8.3.8 onwards, before 8.4.0 */
+ else
peer = DRBD_MAX_BIO_SIZE;
}
